Am. Annaswamy et al., Thermoacoustic instability: Model-based optimal control designs and experimental validation, IEEE CON SY, 8(6), 2000, pp. 905-918
Active control of thermoacoustic instability has been increasingly sought a
fter in the past two decades to suppress pressure oscillations while mainta
ining other performance objectives such as low NOx emission, high efficienc
y, and power density. Recently, we have developed a feedback model of a pre
mixed laminar combustor which captures several dominant features in the com
bustion process such as heat release dynamics, multiple acoustic modes, and
actuator effects. In this paper, we study the performance of optimal contr
ol designs including LQG-LTR and H-infinity methods using the model with ad
ditional effects of mean heat and mean flow, actuator dynamics, and input s
aturation. We also verify these designs experimentally using a 1 kW bench-t
op combustor rig and a 0.2-W loudspeaker over a range of flow rates and equ
ivalence ratios. Our results show that the proposed controllers, which are
designed using a two-mode finite dimensional model, suppress the thermoacou
stic instability significantly faster than those obtained using empirical a
pproaches in similar experimental setups without creating secondary resonan
ces, and guarantee stability robustness.